feat: unified HomeAI dashboard — merge character + desktop into single app

Combines homeai-character (service status, character profiles, editor) and
homeai-desktop (chat with voice I/O) into homeai-dashboard on port 5173.

- 4-page sidebar layout: Dashboard, Chat, Characters, Editor
- Merged Vite middleware: health checks, service restart, bridge proxy
- Bridge upgraded to ThreadingHTTPServer (fixes LAN request queuing)
- TTS strips emojis before synthesis
- Updated start.sh with new launchd service names
- Added preload-models to startup sequence

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

homeai-dashboard/src/hooks/useChat.js

@@ -0,0 +1,45 @@
+import { useState, useCallback } from 'react'
+import { sendMessage } from '../lib/api'
+
+export function useChat() {
+  const [messages, setMessages] = useState([])
+  const [isLoading, setIsLoading] = useState(false)
+
+  const send = useCallback(async (text) => {
+    if (!text.trim() || isLoading) return null
+
+    const userMsg = { id: Date.now(), role: 'user', content: text.trim(), timestamp: new Date() }
+    setMessages((prev) => [...prev, userMsg])
+    setIsLoading(true)
+
+    try {
+      const response = await sendMessage(text.trim())
+      const assistantMsg = {
+        id: Date.now() + 1,
+        role: 'assistant',
+        content: response,
+        timestamp: new Date(),
+      }
+      setMessages((prev) => [...prev, assistantMsg])
+      return response
+    } catch (err) {
+      const errorMsg = {
+        id: Date.now() + 1,
+        role: 'assistant',
+        content: `Error: ${err.message}`,
+        timestamp: new Date(),
+        isError: true,
+      }
+      setMessages((prev) => [...prev, errorMsg])
+      return null
+    } finally {
+      setIsLoading(false)
+    }
+  }, [isLoading])
+
+  const clearHistory = useCallback(() => {
+    setMessages([])
+  }, [])
+
+  return { messages, isLoading, send, clearHistory }
+}